Check file differences in Linux

Following Linux command can be used to check two file line differences.
Before using the command you must sort the file using sort Linux command.

1.) sort err_file_1.txt > sorted_file_1.txt
2.) sdiff err_file_1.txt err_file_2.txt

Output will be shown in Linux terminal. You can write output to file using following command.

1.) sdiff err_file_1.txt err_file_2.txt >output.txt

HTTP GET/POST Example

Following example can be used to send HTTP GET or POST request to web server using JAVA application.

// HTTP GET request
private void sendGet() throws Exception {

String url = "http://seguide.blogspot.com";

HttpClient client = new DefaultHttpClient();
HttpGet request = new HttpGet(url);

request.addHeader("User-Agent", USER_AGENT);

HttpResponse response = client.execute(request);

System.out.println("\nSending 'GET' request to URL : " + url);
System.out.println("Response Code : " + 
                       response.getStatusLine().getStatusCode());

BufferedReader rd = new BufferedReader(
                       new InputStreamReader(response.getEntity().getContent()));

StringBuffer result = new StringBuffer();
String line = "";
while ((line = rd.readLine()) != null) {
result.append(line);
}

System.out.println(result.toString());

}

// HTTP POST request
private void sendPost() throws Exception {

String url = "http://seguide.blogspot.com";

HttpClient client = new DefaultHttpClient();
HttpPost post = new HttpPost(url);

post.setHeader("User-Agent", USER_AGENT);

List urlParameters = new ArrayList();
urlParameters.add(new BasicNameValuePair("name", "sujith"));
urlParameters.add(new BasicNameValuePair("pass", "abc123"));
urlParameters.add(new BasicNameValuePair("param1", "param1"));
urlParameters.add(new BasicNameValuePair("param2", "param2"));

post.setEntity(new UrlEncodedFormEntity(urlParameters));

HttpResponse response = client.execute(post);
System.out.println("\nSending 'POST' request to URL : " + url);
System.out.println("Post parameters : " + post.getEntity());
System.out.println("Response Code : " + 
                                    response.getStatusLine().getStatusCode());

BufferedReader rd = new BufferedReader(
                        new InputStreamReader(response.getEntity().getContent()));

StringBuffer result = new StringBuffer();
String line = "";
while ((line = rd.readLine()) != null) {
result.append(line);
}

System.out.println(result.toString());

}

Change permission for user in Linux

Following set of commands can be used to change the permission of a user.

Change directory

           sujithde@ewaps1:~> cd delight/

Change permission for user oracle

           sujithde@ewaps1:~/delight> setfacl –R -m user:oracle:rwx .

Add user a mask

           sujithde@ewaps1:~/delight> setfacl –R -m mask:rwx .

Note : –R will recursively change permission for sub folders. 

Run SQL script in Background in MySQL server

Following command can be used to run SQL script in background in MySQL server.

mysql --user=sujith --pass=123suji --database=postdb --host=localhost script_file results.out &

This will return output of script  to result.out file.

JAVA 8 Lambda Expression

Following example explain how Lambda Expression can be implemented in JAVA 8.

    interface MathOperation {

        int execute(int a, int b);

    }

    public int calculate(int a, int b, MathOperation op) {

        return op.execute(a, b);

    }

    public static void main(String[] args) {

        Lamda lamda = new Lamda();

        MathOperation addition = (a, b) -> (a + b);

        MathOperation substract = (a, b) -> (a - b);

        System.out.println(lamda.calculate(4, 5, addition));

        System.out.println(lamda.calculate(4, 5, substract));

    }

Add words to file in linux

Following Linux commands can be used to add words to file.

1) open file in Linux vi editor
2) ESC and type following command as you referred

:/s/^/0/g
add zero(0) to in front of each line
^ defines the start of the line

:/s/$/0/g
add zero(0) to end of each line 
$ defines the end of the line

:/s/718/0/g
replace "718" with zero(0)

Update MySQL table appending text

Following SQL command can be used to update MySQL table with appending text "text" for field "field".

update table set field=concat('text',field);